The concept of nesting one or more smaller containers within a larger container to provide a single shelf keeping unit (SKU) is desireable when two or more materials are to be used together or close in time as part of a single process. This allows mixing of reagents together immediately prior to use to ensure freshness or in the case when two or more substances are not stable together; reduces loss or misplacement of smaller containers; and facilitates storage of the entire unit. Nested containers are very desireable for items such as shampoo/conditioner, permanent wave solution/active substance, hair dye solution/active substance, and so on. These units are usually comprised of a larger container which contains the main liquid and a smaller nested container which contains smaller amounts of a second substance designed to be used in combination or close in time to the main liquid. Nested containers are not new.
U.S. Pat. No. 251,566 dated Dec. 27, 1881 describes one of the first nested containers. It discloses a flat shouldered, glass bottle bearing on its lateral shouldered side a recessed cavity of size sufficient to hold a small glass syringe. The syringe, intended to be used for inoculating subjects with the bottle contents, is inserted into the cavity lengthwise from the top and is prevented from falling out laterally because the lateral opening of the cavity is smaller than the diameter of the syringe.
U.S. Pat. No. 519,601 dated May 8, 1894 discloses a composite glass bottle wherein a number of smaller vessels are nested into vertical recessed cavities running from shoulder to base of a larger round central bottle. The nested vessels are screw capped and held in their cavities by small vertical pipes extending upward from the screw caps to terminate into the cork of the main bottle. The main cork is then removed to allow access to the nested containers.
U.S. Pat. No. 849,211 describes a glass bottle containing a recessed cavity or pocket which extends inwardly into the bottle immediately adjacent to the bottle wall. The pocket opens at the outer surface of the bottle and is of a size sufficient to insert a label, or trademark. Once the desired item is inserted into the pocket the chamber is sealed to provide a bottle whose label is readable through the glass yet cannot be removed or obliterated.
In U.S. Pat. No. 2,493,922 the disclosed container provides a bottle with a conventional neck and stopper with channels or openings arranged in the side walls thereof for carrying a plurality of capsules. The capsules or tablets, designed to be used with the container contents, are removed from the channel by inserting a finger into the open side of the channel and moving the capsule up through the channel opening.
U.S. Pat. No. 2,780,225 describes a blood collection unit comprised of a large glass bottle containing on is outer surface two vertical recessed cavities of size sufficient to nest two test tubes. Both test tubes are removably placed in cylindrical metal holders to facilitate their easy removal to conduct lab tests, etc. The cylindrical metal holders containing both test tubes are held in the recessed cavities by a gummed label passing around the bottle.
U.S. Pat. No. 4,235,343 describes a container assembly comprised of one square flat, shouldered bottle and two smaller flat, shouldered bottles. The large bottle contains on each flat side recessed cavities of size sufficient to hold the two smaller bottles. When the smaller bottles are fitted within the cavities an uninterrupted surface contour results.
However, a chronic problem with all nested containers is securing the smaller nested container within the recessed cavity of the larger container. Labels, cylindrical tubes, pipes and other devices are used, all of which create a more cumbersome system and greatly restrict the size and shape of the smaller nested container. None of the known nested containers provide a system in which the smaller container is removably secured by snapping into the recessed cavity of the larger container.